The district attorney of Nevada County said he will wait until after serial killer Joseph Naso is sentenced in Marin Superior Court before deciding whether to prosecute him in the 1992 death of a Bob Dylan groupie.

District Attorney Clifford Newell said the investigation is incomplete as to where Sara Dylan, whose skull was found in Nevada County, actually died. In any case, Naso is already facing a potential death penalty following his conviction Tuesday by a Marin jury, Newell said.

“If he gets a death sentence it would be a little bit of a waste of taxpayers’ dollars to prosecute the case,” Newell said Wednesday. “How many times can you kill a guy?”

Naso, 79, was found guilty Tuesday of murdering four prostitutes whose bodies were dumped in Marin, Contra Costa and Yuba counties between 1977 and 1994. The prosecution said the victims were four of the women on Naso’s “list of 10” – an alleged roster of unnamed murder victims and the approximate sites were he dumped their bodies.

During Naso’s trial, prosecutors said the evidence also points to Naso’s involvement in the death of Sara Dylan in Nevada County. Authorities suspect she is victim No. 8 on Naso’s list, which includes the phrase “near Nevada County.”

Dylan, whose birth name was Renee Shapiro, was a fan of the singer Bob Dylan and changed her name to match his ex-wife’s. She followed Dylan’s tour around the world, sometimes hitchhiking between shows, and disappeared in 1992 while Dylan was playing in Northern California.

When Naso was arrested, police found Sara Dylan’s passport among Naso’s possessions in a bank deposit box.

Prosecutors did not receive DNA confirmation on Dylan’s skull until shortly before the trial, too late to add another murder charge.

The victims for whom Naso was convicted were Roxene Roggasch, 18, who was found off Sir Francis Drake Boulevard near Fairfax in 1977; Carmen Colon, 22, found near Port Costa in 1978; Pamela Parsons, 38, found in Yuba County in 1993; and Tracy Tafoya, 31, found in Yuba County in 1994.

Authorities are still investigating other entries on the “list of 10,” which includes a reference to a “Girl on Mt. Tam.”

Naso, a retired photographer, kept an extensive journal that documented rapes and sexual assaults dating to the 1950s. The journal and other evidence that led to his arrest were seized during a 2010 probation search at his home in Reno.

Naso acted as his own lawyer during the two-month trial.

The jury that convicted Naso returns to court Sept. 4 to decide whether he should receive a death sentence.

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